Condenser



y 30, 1929- w. DUBlLlER 1,722,325

CONDENSER Original Filed Feb. 14, 1924 llnllllllln'l I 1:!!411101111 1 v V a; t Z 24 1 v 2 "gen 5: 1) 74 z t 76 2 1g%l4' a arm,

Patented July 30, 1929.

wrLLmmi DUBJIIER, or NEW ROCHELLE, NEW YORK, ASSIGNOR TO DUBHZIER CON- DENSER AND RADIO CORPORATION, A CORPORATION OF DELAWARE.

CONDENSER.

,Application filed February 14, 1924, Serial No. 692,864. Renewed December 20, 1928.

My invention rel-ates to condensers, and more particularly to variable condensers of the type used in radiocommunication.

An object of my invention is to provide a condenser in which gradual adjustments of capacity may be effected with facility, and with a minimum of friction of the parts.

Another object of my invention is to provide a condenser structure in which the fixed element is attached to the support in a simple, yet extremely sturdy manner, whereby the condenser may be capable of long continued use withoutfear of injury to the fixed element.

A further object of my invention is to provide means for effectively preventing displacement of the flexible element in the operation of the condenser, and also to provide a structure in which the compression plate for operating the resilient element is limited.

Yet another object of my invention is to provide a construction having an easily formed and positively operable type of contact for making with the movable element ofthe condenser.

With these and other objects in view which may be incident to my improvements, the invention consists in the partsand combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention, may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the ac- I companying drawings means for carrying the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings Fig. 1 is a top plan view of my variable condenser;

Fig. 2"is a view inside elevation of the form shown in Fig. 1; Fig. 3 is a view in cross section, taken on the line 3-3 of Fig. 2, looking in the direction of the arrows;

Fig. 4 is a cross section-a1 view of my conthe movement of electrical connection layers,

riveted in place,

denser taken on the line H of Fig. 2, looking in the direction of the arrows.

my invention, the fixed element comprises a sheet of metallic foil fixed to a suitable insulating support, the metallic foil being covered by an insulating sheet of mica which extends beyond the edge of the foil,

forming a pro ecting overlapping insulating sheet which prevents possible injury to the edge of the metallic foil. The metallic foil and the mica sheet are held to the support by means of eyelets which are passed through the support, the metallic foil and the insulating mica sheet, and are riveted in place to maintain holding washers ,in firm contact with the mica sheet, The resilient movable element of the condenser comprises a" bow or U-shaped metal strip, whose center is adapted to contact against the insulating mica sheet of the fixed ele ment. A guiding yoke is attached to' the support for the fixed element, and prevents displacement of the movable element of the condenser. v

Within the yoke is adapted to move a compression plate against which bear the ends of the movable element. A reciproeating shaft operated by the movement of a screw within an operating knob causes the compression plate to approach or recede from the fixed element, thereby causing the resilient movable element to be progressively laid down on and picked up from the surface of the fixed element. A U-shaped contact clip is adapted to contact with either edge of the resilient movable element to make electrical connection therewith, in all adjustments of the condenser.

Referring to the drawings for a more detailed description, I have shown an insulating support 1, of bakelite or some other suitable insulating material. Fixed to the suport 1 at itsunder side by some suitable adesive is a strip of metallic foil 2, and overlyingthe metallic foil 2 is an insulating sheet of mica 3. whose edges project beyond the edges of the metallic foil to protect it from injury; the support 1, the metallic foil 2 and the insulating sheet of mica 3 are eyelets 4. The eyelets 4 are inserted through the various and holding washers 5 are slipped over the eyelets so that when the eyelets are the holding washers 5 see Fig. 2. Passing through firmly hold the mica sheet 3 which is preferably also adhesively attac ed to the metallic foil 2, against the metal foil and the whole against the support 1.

The metallic foil 2 and the mica sheet 3 comprise the fixed element of my condenser. To make electrical connection with the fixed element, I have provided a binding 'post 6. Over the head of the binding post is passed a contact washer 7 which is pressed against the metallic foil 2 through an aperture 8 cut in the insulating mica sheet 3. The end of the bindin post 6, which projects upwardly through t 1e support 1, is screw-threaded. Electrical connection is adapted to be made to the binding post by placing a wire terminal between the metallic washer 9, and a nut 11 carried by the binding post 6. By tightening the nut 11, a terminal wire may be firmly held in position.

Fastened to the support 1 by means of screws 12, is a yoke 13 of insulating material 1 having downwardly depending parallel sides 14, which project below the fixed element of the condenser. The yoke 13 is formed with a protruding central support 15. The sides 14 have cut out portions 16 therein, which lightens the construction. Passing through the depending parallel sides 14 are stop bars 17, comprising bolts which pass through ,from one side to the other, and are held in place by means of nuts 18. The stop bars 17 act to limit the movement of the movable element of the condenser in its minimum settin as" will be hereinafter explained.

Kdapted to contact at substantially its middle point against the insulating mica sheet 3 of the fixed element of the condenser. is a flexible resilient metallic strip 19, of 'U, or bow shape. The free ends 21 of the strip 19 bear against and are adapted to slide upon a metallic compression plate 22, which is aflixed at substantially its middle by means of a screw 23 to a reciprocable shaft 24. Downward movement of the compression plate 22 is limited by'the stop bars 17. The reciprocable shaft 24 passes through an aperture 25 formed in the resilient metallic strip 19 that operates as the movable element of my condenser. There is an opening 26 formed in the mica strip 3 of the fixed element, and" an opening 27 formed in the foil 2, to permit the passage of the reciprocablc shaft 24 through the fixed element of the condenser. The reciprocating shaft 24 passes through an opening 28 formed in the support 1. and an opening 29 formed in the support 15 of the yoke 13. The aperture 27 formed within the foil 2, causes the foil to clear the reciprocating shaft 24 by a sub stantial margin, to prevent any possibility of electrical contact of the foil 2 with the shaft 24.

The support 15 is providedwith an annular flange 31. Lying on top 0% this annuiar flange 31 is a metallic washer 32 which is depressed at 33 into a depression formed in the upper surface of the support 15. This prevents the washer 32 from rotating. The washer 32 is provided with a tab or lug 34 which fits into a slot 35 formed within the shaft 24. The tab 34, by reason of its engaging the slot 35, prevents possible rotation of the shaft 24.

Mounted over the support 15 and having its lower surface contacting with the washer 32 is an operating knob v36 of insulating material. The knob 36 is provided with an inner metallic hollow member 37 which is keyed to, or fitted tightly into, the operating knob 36, and is adapted to rotate with the knob. The metallic hollow member 37 is provided with internal screw-threads 38 engaging with screw-threads 39 formed on the reciprocating shaft 24. To hold the operating knob in operative position, I have provided a U-shaped holding piece 41 of resilient metal, which enga es the flange 31 formed on the upper end 0? the support 15,

and likewise engages a flange 42 formed on operating knob in operative position. To

hold the U-shaped holding piece 41 in place after being fitted over the flanges 31 and 42, 1 have provided a bolt 43 which passes through the free ends 44. A nut 45 holds the bolt in place and prevents the Ushaped holding member 41 from slipping from the flanges 31 and 42, though it is to be understood thatthe holding member is not so tightly adjusted as to prevent free rotation of the operating knob 36.

Upon turning the operating knob 36, the screw-threads 38 engage with the screw-' threads 39 of the reciprocating shaft 24 and feed the shaft either in an upward or downward direction. The tab 34 on the washer 32, by engaging with the slot 35, prevents possible rotation of. the reciprocating shaft 24.

To make electrical connection with the movable resilient member 19, I have provided a U-shaped metallic strip 46. The stri 46 comprises a piece of spring metal having downwardly projecting arms 47 which are adapted to fit over the yoke 13 and the support 1. and fit into two 0 iposite openings 16 formed in the downwar ly depending parallel sides 14 of the oke 13. The downwardly projecting arms 4; are inwardly intentioned. as indicated at 48. to make them project inwardly beyond the line of the inner surface of the depending sides 14.

Arms 47 engage and contact with the denser element. Electrical contact is thus maintained at all positions of the condenser between condenser element 19, compression plate 22, and the arms 17 ot' the U-shaped metallic strip 46. The strip 46 is held in place on the yoke 13 by means of a binding post 49, whose head 51 is countersunk in the under surface of the yoke 13. The upwardly projecting end 52 of the binding post 4.9 is screw threaded, and a nut 53 operates on the screw-threads. Electrical connection may be made, through a proper terminal, with the movable element of the condenser, by placing a terminal wire between the strip 46 and the nut 53 and tightening the nut.

In operation, by turning the operating knob 36, the reciprocable shaft 24 may be rased or lowered to raise or lower the com-- prcssion plate 22 which causes the resilient U-shaped movable element of the condenser to be laid down on or picked up from contact with the fixed element of the condenser, thus varying the capacity. The maximum capacity is attained when the compression plate is at its utmost upper position. The

minimum capacity of the device is attained when the compression the stop bars 17.

The resilient movable element 19 of the condenser is prevented from becoming displaced and affecting the operation of the condenser by reason of the downwardly depending sides 14 of the yoke 13. Should the condenser element 19 slip slightly to one side, it can go no further after it contacts with the inner surface of the downwardly depending sides 14. The stop bars 17 prevent possible movement of the compression plate 22 below the lower ends of the sides 14 of the yoke 13, and hence the condenser element 19 can not slip out of place.

While I have shown and described the preferred embodiment of my invention, I

wish it to be understood that I do not confine myself to the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope ofthe appended claims.

In Figure 2, the mica, and adjacent parts 14 are shown broken away to disclose the hole 8.

I claim 1. A variable condenser comprising a fixed electrode, dielectric material adjacent said electrode, a resilient electrode of opposite polarity adapted to be flexed into contact with the dielectric material by movement of its ends, and'a guiding means for the resilient electrode.

2. A variable condenser comprising a sup-' port, an electrode of one polarity, dielectric material ad acent said electrode, a resilient plate is arrested by electrode of opposite polarity adapted to be flexed into contact with the dielectric material, and means attached to said support for guiding the resilient electrode.

3. A variable condenser comprising a support, an assembly including a fixed electrode and a dielectric member secured to one side of the support, a U-shaped resilient electrode of opposite polarity adapted to be flexed into contact'with the dielectric member by movement of its ends, a guiding yoke for the re silient electrode attached to the support, a compression plate on which said ends of the resilient electrode bear, and tension means to pull the compression plate towards the fixed assembly.

A. A variable condenser comprising a fixed electrode, a resilient electrode of opposite polarity having movable ends, dielectric material interposed between said electrodes, a

yoke for guiding said movable ends, means 'for making electrical connections with the fixed electrode, the movable ends contacting with the compression plate, and means for forcing the compression plate toward the fixed electrode.

5. A variable condenser comprising a fixed element, a resilient movable element, a compression plate, a yoke for guiding the movable element, means for making electrical connection with the fixed'element, a plurality of metallic strips bearing on the edge of the compression plate to make electrical contact therewith, and means for flexing the resilient element.

6. A variable condenser comprising a fixed elect-rode, a resilient movable electrode, 'a compression plate on which the ends of the resilient electrode bear, a yoke for guiding the movable electrode, a U-shaped metallic strip straddling the movable electrode and having both arms contacting with either 'edge of the compression plate, and means to flex the movable electrode.

7. A variable condenser comprising a fixed electrode, dielectric material adjacent thereto, a resilient movable electrode having a central portion contacting with the dielectrio material, and end portions adapted to be flexed into contact therewith, a guiding means for the movable electrode, and means to limit he movement of said end portions away from the fixed electrode.

8. A variable condenser comprising a su port, a fixed assembly including an electroc e and a dielectric member, a resilientelectrode of opposite porality adapted to be flexed into contact with the dielectric member by movement of its ends, and a guiding yoke for the movable ends fitting over the support and the fixed assembly, and means to limit the movement of the said ends away from the fixed assembly.

9. A variable condenser comprising a support, a. fixed plate of one polarity mounted thereon, a U-shaped resilient movable plate of opposite polarity, dielectric material in terposed between said plates, a compression plate on which the ends of the movable plate bear, means for moving the compression plate towards and away from the fixed plates, a guiding yoke for the movable plate fitting over the support and the fixed plate, and means carried by the guiding yoke for limiting the movement of the compression plate away from the fixed plate.

10. A variable condenser comprising a support, a fixed plate electrode mounted thereon, a U-shaped resilient movable electrode, a compression plate on which the ends of the movable electrode bear, a reciprocating shaft passing through the support and attached to the compression plate, a screw means to reciprocate the shaft, a guiding-yoke for the movable electrode fitting over the support and the fixed electrode, and means carried by the guiding yoke for limiting the movement of the compression plates away from the fixed electrode.

11. A variable condenser comprising a fixed electrode, a resilient electrode of opposite polarity in spaced relation thereto and at one side thereof, the resilient electrode having movable-ends, a reciprocating shaft, a plate operated by the shaft to flex the ends of the resilient electrode towards the fixed electrode, an operating knob on the opposite side of the fixed electrode and operable to reciprocate the shaft.

In testimony whereof I affix my signature.

WILLIAM DUBILIER. 

